Within the framework of this document, the abbreviation “TCU” is understood to mean any transmission control unit for controlling a motor vehicle transmission, any clutch control unit for controlling one or more motor vehicle shifting clutches, and in particular any control unit for controlling a transmission as well as for controlling one or more shifting clutches, in particular any control unit for controlling a dual-clutch transmission. Dual-clutch transmissions have long been known, and are described, for example, in German reference no. DE 10 2008 023 360 A1 (Eich et al.). The terms “TCU” and “control unit TCU” are used synonymously.
Within the framework of this document, the abbreviation “HCA” is understood to mean any actuator, for example, for operating an automated friction clutch, for example, a hydraulically operated clutch actuator, in particular a hydrostatically operated clutch operator (hydrostatic clutch actuator) as disclosed, for example, in German reference no. DE 10 2010 047 801 (Franz et al.) or German reference no. DE 10 2010 047 800 (Gramann et al.). However, every HCA must have at least one non-volatile memory as well as one local control unit (LCU) unambiguously and firmly assigned to it. The non-volatile memory is located, for example, in the local control unit (LCU) of the HCA.
Dual-clutch transmission systems have, for example, a TCU HCA system.
The abbreviation “SW” is to be understood within the framework of this document to mean software.
Within the framework of this document, the terms diagnostic routine, diagnostic function, diagnostic service and diagnostic command are used interchangeably or essentially synonymously.
Within the framework of this document, the terms software, routine, function and process are likewise used essentially synonymously.
The components used, for example, in dual-clutch transmissions, depending on their design, have one or more control units, including flash memories for the application SW. A SW update may become necessary due to model year updates or error correction (bug fixes).
In dual-clutch systems, normally two actuators are used (one actuator for each clutch), such as, for example, the HCA, whose control unit (LCU) is also equipped with a flash memory. Since the same application SW is used for both LCUs, for reasons of simplification, in the event of a SW update both LCUs must also be updated, each LCU separately. The flash process is usually initiated, carried out and monitored for correct execution by a test device. The flash process takes place via a CAN bus, with the control unit (TCU) connected ahead of the LCU enabling the connection between LCU and tester by means of a gateway function.
The program memory within the LCU is very limited; integrating additional SW functionality must always be reconsidered therefore against the background of the limited memory resources.
In particular, the function which enables the updating of the control unit code (LCU application SW) of the HCA is rarely needed but—if it is carried out by means of the client-specific diagnostic protocol—still demands extensive memory space. By protocol, it is meant a communication protocol, which is well known in the art as a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. These are the rules or standard that defines the syntax, semantics, and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. A different protocol, for example Open-source CAN Calibration Protocol (CCP) or Universal Measurement and Calibration Protocol (XCP), which is used for this purpose during development, requires much less memory space.
As shown in FIG. 1, the flashing of LCU 150,160 always takes place by means of diagnostic tester 140; there is usually no direct connection of LCU 150,160 to tester 140, but rather—by means of a gateway function in TCU 110—only through transmission control unit TCU 110. TCU 110 forwards 120 the commands from the tester to the LCU, and as a countermove returns 130 the responses of the LCU to the tester. All of this takes place via the client-specific diagnostic protocol, for example, the Unified Diagnostic Services (UDS) protocol, which must be stored both in TCU 110 and in the LCU for this purpose. The gateway function allows change-free transmission of the messages in both directions. Such methods are also explained, for example, in German Patent No. DE 101 53 085 A1 (Gruenewald et al.), German Patent No. DE 43 15 494 C1 (Keuhner et al.), German Patent No. DE 102 37 715 A1 (Bolz) and German Patent No. DE 196 16 166 A1 (Fackler).